In the construction of mobile units for removing leaves and other debris from a lawn, driveway or other surface, it is sometimes desirable to collect the leaves and debris by means of a portable vacuum cleaner of the general type disclosed in U.S. Pat. No. 3,534,429 which issued to the assignee of the present invention. In such a vacuum cleaner, a gasoline driven engine is mounted on a frame which is supported by a set of wheels, and the engine shaft drives an impeller located within a centrifugal-type blower housing which is mounted on the engine. As disclosed in the above patent, the blower housing has a center inlet which is connected to a suction inlet nozzle and has a tangential outlet which directs the collected debris into a bag-like container located rearwardly of the engine between a handle assembly projecting upwardly and rearwardly from the frame.
It is also common to remove leaves and other debris from a surface by means of a mobile blower unit which does not incorporate a suction inlet nozzle and a collection bag or container, but simply directs a blast of air from the blower outlet towards or across the surface. In such a mobile blower unit, frequently the blower housing is mounted so that its outlet is in a low position adjacent the ground surface to produce a tangential air blast from the bottom of the blower housing generally parallel with the ground or other surface. It is also common to mount the blower housing on the engine with the blower outlet in a high position so that the air blast is directed downwardly from the top of the blower housing at an incline towards the ground or surface.
When the outlet of the blower housing is located in a high position, it has been found desirable to mount an adjustable air deflector on the outlet portion of the blower housing and to provide the operator of the blower unit with means for adjusting the position of the deflector to vary the angle at which the air blast is directed against the ground or other surface. For example, when fallen leaves have become wet and soggy, the leaves become matted and are difficult to move unless the air blast is directed downwardly at an acute angle under the leading edge of the matter leaves. By adjusting the position of the deflector assembly, the operator can precisely select the angle at which the air blast is discharged according to the volume of collected leaves or debris, the degree of wetness and the type of surface.
On the other hand, when the leaves are dry and the ground surface is covered by long grass, it is sometimes desirable to have the blower outlet in a low position with the air blast directed generally parallel to the ground surface. However, after a mass of dry leaves have been collected in a windrow, the air blast from a low position outlet tends to blow holes or tunnels within the windrow of leaves. It is then desirable to have a blower with its outlet in a high position and with the air blast directed downwardly so that the windrowed leaves can be more effectively rolled or moved.